Search results for "molecular mass"
showing 10 items of 155 documents
Calculation of the molecular masses of two newly synthesized thermostable enzymes isolated from thermophilic microorganisms
1995
Two thermostable enzymes synthesized by thermophilic microorganisms were isolated and purified. A thermostable beta-galactosidase was produced in a continuous fermentation process by Bacillus stearothermophilus TP 32 as an intracellular enzyme. After applying different concentration procedures the raw extract enzyme was prepurified on a Sephadex G-200 size exclusion column. The isolated beta-galactosidase fraction was then separated with HPLC on a TSK G 3000 SW size exclusion column to determine the molecular mass based on calibration curves of standard proteins. The other enzyme, a thermostable protease, was synthesized by Bacillus stearothermophilus TP 26 as an extracellular enzyme. After…
Syntheses and properties of gel chromatography materials
1970
Abstract The effect of the mode of synthesis on the characteristics of cross-linked polymers is examined for cross-linked copolymers of ethylvinylbenzene-divinylbenzene and vinyl acetate-divinyl adipate. For homogenously cross-linked gels the amount of cross-linking agent determines the “pore size” of these gels in the swollen state. Decreasing the amount of the divinyl component results in gels with an increase in the excluded molecular weight. The mechanical stability sets the experimental limit of their usage, so this type of gel is mostly suited for the separation of oligomers; polymers, however, may be separated by use of heterogenously cross-linked gels. The latter type of gel is prep…
Dairy Debaryomyces hansenii strains produce the antihypertensive casein-derived peptides LHLPLP and HLPLP
2015
The ability of dairy Debaryomyces hansenii, Kluyveromyces lactis and Kluyveromyces marxianus strains to release the casein-derived antihypertensive sequences RYLGY, AYFYPEL, LHLPLP, HLPLP, VPP and/or IPP was examined. Yeast strains were grown in medium with casein as sole nitrogen source and the yeast casein hydrolysates (CSHs) were analysed by HPLC-MS/MS to search for the six antihypertensive sequences. Only LHLPLP and HLPLP were identified in CSHs and exclusively in D. hansenii Dh1 and Dh14 hydrolysates in which both antihypertensive sequences represented approximately 6 (CSH Dh1) and 10% (CSH Dh14) of total peptide content. In addition, a complete analysis of selected CSHs by HPLC-MS/MS …
Polymer-polymer interaction parameters in solvent/polymer/polymer ternary systems
1981
Abstract Empirical equations defining the relationships between b23 and χ23 interaction parameters for the ternary systems toluene (1)/poly(dimethylsiloxane), PDMS, (2)/polystyrene, PS, (3) and benzene (1)/PDMS(2)/PS(3) have been determined. The dependences of both interaction parameters on the mean molecular weights of the macromolecular components have also been studied. A single dependence of b23 (or χ23) upon the mean molecular weight is found when both polymeric components have intermediate to high molecular weights. However, that single dependence is not found when the molecular size of polymer (2) is low.
Wall mannoproteins of the yeast and mycelial cells of Candida albicans: nature of the glycosidic bonds and polydispersity of their mannan moieties.
1988
SUMMARY: Zymolyase released between 20 and 25% of the total protein from purified walls of yeast (Y) and mycelial (M) cells of Candida albicans. The material released contained 92% carbohydrate (86% mannose and 6% glucose) and 7:< protein. Over 85% of the carbohydrate was N-glycosidically linked to the protein and the rest (less than 15%) was linked O-glycosidically. Highly polydisperse, high molecular mass mannoproteins, resolved by electrophoresis as four defined bands in Y cells and two bands in M cells, had both types of sugar chains. A 34 kDa species found in both types of cells had a single 2.5 kDa N-glycosidically linked sugar chain and a 3 1.5 kDa protein moiety. Polydispersity in t…
Acid tolerance inLeuconostoc oenos. Isolation and characterization of an acid-resistant mutant
1996
The acid tolerance ofLeuconostoc oenos was examined in cells surviving at pH 2.6, which is lower than the acid limit of growth (about pH 3.0). Acid-adapted cells survived better than non-adapted cells. Tolerance to acid stress was found to be dependent upon the adaptive pH. Acid resistance was increased by an order of magnitude for cultures adapted to a pH of about 2.9. Inhibiting protein synthesis with chloramphenicol prior to acid shock revealed that acid adaptation may involve two separate systems, one of which appears to be independent of protein synthesis. The acid-resistant mutant LoV8413, isolated during a long-term survival screen at pH 2.6, was found to be able to grow in acidic me…
Novel acrylamido monomers with higher hydrophilicity and improved hydrolytic stability: III. DNA separations by capillary electrophoresis in poly(N-a…
1996
Separation of DNA fragments in a novel polymer network, consisting of N-acryloylaminopropanol (AAP) is reported. The performance of this novel monomer, as a sieving liquid polymer in capillary zone electrophoresis, was evaluated. In 50 microns ID capillaries, an 8% solution of poly (AAP) can afford apex-resolution of the 123/124 bp adjacent pair of DNA fragments in marker V, typically unresolved in any poly (acrylamide) formulation. It is proposed that the distal-OH group in the AAP molecule can form transient H-bonds with the DNA double helix. Molecular modeling shows a meandering structure for poly (AAP), lacing the walls of half a cylinder, with kinks protruding at regular intervals, pot…
Entanglement Transition in Hyperbranched Polyether-Polyols
2010
Are hyperbranched polymers capable of forming entanglements? This is the central issue of this contribution. Hyperbranched polyglycerol (hbPG) samples with different molecular weights (600-106 000 g · mol(-1) ), narrow polydispersities (1.2-1.8) and high degrees of branching (≈0.6) were prepared by anionic ring-opening polymerization. The viscoelastic properties of these polymers with respect to molecular architecture and molar mass were investigated. At low molecular weights "classical" scaling behavior between zero shear viscosity and molecular weight can be observed, whereas between 3 000 and 10 000 g · mol(-1) a plateau-like area is found. The results indicate entanglement dynamics when…
Differential localization of two acid proteinases in germinating barley (Hordeum vulgare) seed
1995
A cathepsin D-like aspartic proteinase (EC 3.4.23) is abundant in ungerminated barley (Hordeum vulgare) seed while a 30 kDa cysteine endoproteinase (EC 3.4.22) is one of the proteinases synthesized de novo in the germinating seed. In this work, the localization of these two acid proteinases was studied at both the tissue and subcellular levels by immunomicroscopy. The results confirm that they have completely different functions. The aspartic proteinase was present in the ungerminated seed and, during germination, it appeared in all the living tissues of the grain, including the shoot and root. Contrary to previous suggestions, it was not observed in the starchy endosperm. By immunoblotting…
Acid Carboxypeptidases in Grains and Leaves of Wheat, Triticum aestivum L
1986
Extracts of resting and germinating (3 days at 20 degrees C) wheat (Triticum aestivum L. cv Ruso) grains rapidly hydrolyzed various benzyloxycarbonyldipeptides (Z-dipeptides) at pH 4 to 6. Similar activities were present in extracts of mature flag leaves. Fractionation by chromatography on CM-cellulose and on Sephadex G-200 showed that the activities in germinating grains were due to five acid carboxypeptidases with different and complementary substrate specificities. The wheat enzymes appeared to correspond to the five acid carboxypeptidases present in germinating barley (L Mikola 1983 Biochim Biophys Acta 747: 241-252). The enzymes were designated wheat carboxypeptidases I to V and their …